This invention concerns in general a mattress cushion, and more particularly a cushion (or pad) for use on a mattress with a fitted or flat sheet secured on top thereof. A mattress cushion in accordance with this invention may be comprised of a resilient material having a plurality of projections thereon, but with at least one marginal region thereof free from such projections. This marginal region functions as a live edge for compression so as to resiliently receive sheets supplied thereto.
The prior art has long known pads made of resilient material which are intended to be placed on top of existing mattresses as a supplement thereto. Some such mattress pads undoubtedly are intended to be used as a supplement for a mattress, with a fitted or flat sheet subsequently applied thereto. In general, a conventional fitted sheet is one which has preformed corners, usually having elastic therein, to fit snugly over a mattress. The size of the fitted sheet generally is made to prefit certain known standard sizes of mattresses.
Flat sheets generally are rectangular sheets which have no such fitted corners, but which may be snugly fit to a mattress by conventional folding techniques. With regards to either the flat or fitted sheet, it is intended that the sheets fit snugly on the mattress on which they are placed. Sheets which do not form a snug fit are generally undesirable because of the uncomfortable loose fit which results. Hence, fitted sheets are generally more popular than flat sheets with a large number of people because fitted sheets are preformed to fit specific sizes of mattresses.
Prior art mattress pads generally vary the degree of comfort which they add to a mattress by varying their determined pad thicknesses and densities of material. However, additional comfort in the form of additional thickness is conversely proportional to the ease with which conventional sheets may be fit on top of the pad applied to a particular mattress. In other words, the thicker the pad, the more likely it is to push sheets up away from the mattress, and thereby defeat the intended snug fit thereof.
Some pads present a relatively flat or uni-surface profile to the covering which will be placed above them. Examples of such art include the U. S. Pat. to Thompson (4,110,881), the U.S. Pat. to Stalter (4,265,484) and the Canadian Patent to Paul (1,179,789). Such type of pads may include slots or similar cuts into the body of the pad so as to form individual projections or resiliently responsive portions of the pad. Such cuts maximize pad response to loading placed thereon. This particular group of prior art references includes marginal areas surrounding the slotted individualized resilient sections, but such marginal areas have the same height profile as the individual sections. Therefore, the full thickness of the pads still cause sheets placed thereon to be repelled upward away from the mattress to which they are intended to be secured.
The U.S. Pat. to Neely (2,783,827) discloses a rubber pad for use in upholstered spring construction. The rubber pad has a marginal area which is cut at an angle. The purpose of such an angled marginal area is to be wrapped around the edge of a chair which is being upholstered. Material is secured thereto as illustrated by the figures of Neely. However, the remainder of the rubber pad has no projections thereon, and instead forms a flat surface only. Also, the angled marginal edge once wrapped in its intended place merely provides a convenient flat surface on the side of the upholstered item for securing the covering material thereover with hog rings.
The U.S. Pat. to Legg (658,798) discloses a marginal area which is angled and which surrounds projections of a bed protector. The angled margin is made of solid rubber and intended to serve as an inclined plane surface for slipping the bed protector underneath the occupant of a bed. The solid inner edges of the rubber marginal region surround a plurality of pegs so as to form a moat therearound, for the purpose of retaining any water passed onto the mattress by an occupant. It is not apparent from this patent that there is any intention of placing a sheet between the occupant and the pad since fluids are expected to be passed by the occupant, nor does it appear that the marginal edge made of solid rubber could resiliently receive any such sheet were it to be placed on the bed pad.
U.S. Pat. No. 3,940,811 by Tomikawa, et al. discloses lightweight construction material used as core material for a mattress. Laminations of sheet material are press molded on both sides thereof to form complementary concave and convex patterns. A thin marginal portion of the sheet is not impressed with the concave or convex patterns. However, the resulting element, made of plastic materials such as foamed polyethylene type resin, is only used as an intermediate construction element in the center of a mattress, to be further surrounded by layers of foam on both sides thereof. No final article results which is satisfactory to serve as a supplement between a mattress and conventional sheets applied thereto.
The U.S. Pat. No. 3,258,751 to Kaplan is generally representative of prior art which illustrates a foam pad having a plurality of projections thereon, the pad being applied to a mattress, with a sheet placed on top of the pad and mattress. The general shortcomings of such prior art articles are further discussed below in conjunction with prior art FIG. 3a of this application.
In general, numerous other prior art padding articles are known including some made of various foam materials and having various projections, but none of which are concerned with the particular features of the present invention. Examples of such prior art articles include:
______________________________________ Inventor U.S. Pat. No. Issue Date ______________________________________ Frankenburg 4,326,310 Apr. 27, 1982 Koepke 3,713,697 Jan. 30, 1973 McGregor, Jr. et al. 2,785,739 Mar. 19, 1957 Kay 2,620,494 Dec. 9, 1952 Doane 2,609,548 Sept. 9, 1952 Belian 2,184,808 Dec. 26, 1939 ______________________________________